The present invention concerns the manufacturing of semiconductor circuits and pertains particularly to a virtualized generic equipment model data and control router for factory automation.
The semiconductor manufacturing process is made up of a significant number of unique semiconductor materials processing steps. At each step the material is exposed to various mechanical, chemical or electrical processes that either change or measure the nature of the semiconductor material. Each one of these steps requires a unique and highly specialized materials processing tool.
In any given fabrication manufacturing process step, there are typically five common actions performed. In the first action, the material (e.g., a silicon wafer) arrives at a tool. At the tool, the material is detected, identified and onloaded.
In a second action, the material is moved into a process chamber. In a third action, the material is processed. In a fourth action, the material is moved out of the process chamber. In a fifth action, the material is offloaded from the tool.
In the first, second, fourth and fifth action, the material is transported and these actions are collectively referred to as the materials transport function. In the third action, the material is processed and this action is referred to as the materials processing function. Typically the materials transport function and the materials processing function are integrated into a single process tool.
Either a cell controller or a factory host system manage the automation of a collection of tools. Herein, the factory host and the cell controller are both referred to as the “process step host” or “automation host”. For each tool, the process step host typically has one communication path and manages one process state model. This one to one relationship of communication, state model and process step provides an easy method of managing the automation.
There are cases, however, where it takes multiple physical tools to accomplish the five actions for a single manufacturing process step. The most prevalent case of this is the material test process step, where the five steps of the materials processing function and the materials transport functions described above are typically three separate tools.
For example, materials onload and offload are accomplished by an automated materials transport and docking system typically known as an Equipment Front End Module (EFEM). Materials movement within the process step is accomplished by a materials handling system typically known as a prober or handler. Materials processing for the test process step is accomplished by a test system.
Herein, a process step that requires these multiple physical tools to complete the step is referred to as a non-integrated materials transport process step. For a non-integrated materials movement process step, the process step host is not only managing the process step, but also has to micromanage the relationship between the multiple tools required to accomplish that single process step. Unlike an integrated materials movement tool, the process step host must keep track of multiple individual process state models and multiple communication paths for a single process step.
In order to provide a common framework for the automation of the semiconductor manufacturing processes, semiconductor manufacturers rely upon mechanical and software standards developed by several industry wide consortiums. These automated manufacturing processes include both the individual process step tools, and the manufacturing process cells made up of several individual process tools under the direction of the process step host computer. The vast majority of these automation standards are issued by the Semiconductor Equipment Manufacturers Institute (SEMI). The fundamental communication standards that govern the process step host to tool communication and behavior are the SEMI E4, E5 E30 and E39 standards. These standards are commonly known as the SEMI SECS/GEM standards. SEMI also provides an additional standard, E87, which provides for the management of materials carriers used to transport material between process steps and process tools.
One particular aspect of SEMI E30 and E87 is that they require the process tool to provide and maintain an equipment process state model. This model allows the automation function to track and understand the physical and logical behavior of the process tool. By following the process tool's behavioral process state model, the automation function can understand what the process tool is doing, and what it is valid and able to do next. SEMI E30 and E87 also require the process to provide and maintain control, port, and communication state models.
In the specific case of 300 mm semiconductor fabrication facilities (fabs), the application of the relevant SEMI and other standards is further described by the CIM Global Joint Guidance for 300 mm Semiconductor Factories (GJG) issued by International Sematech (ISMT) and the Japan 300 mm Semiconductor Technology Conference (J300).
The GJG provides an important, specific requirement for manufacturing process automation that is a critical concern for nonintegrated materials handling process step implementations. GJG CIM Guidelines Revision 5, Section 1, Paragraph 1.1 states:
A single physical communication connection must link the production equipment to the host. A single physical communication connection means that the Equipment Front End Module (EFEM) is integrated through the production equipment rather that connected directly to the host.
With respect to the materials test process step, the above-quoted requirement means that the carrier management capabilities of the EFEM, the materials movement capabilities of the prober, and the materials processing capabilities of the test system, must all be controlled and communicated to the process step host via a single, integrated communications link.
The non-integrated materials process step requires a much higher level of control, and causes problems when trying to meet the requirements of the SEMI and GJG standards that govern the process step. The common implementations of the SEMI standards assume that a single tool accomplishes the process step, and that the materials movement function and materials processing function are all accomplished by that single tool. The GJG requires both functions be connected to the process step host via a single communications link.